Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Infection Biology and Microbiology > Lecture 6: Bacterial Motility + Introduction to pili/fimbriae > Flashcards

Lecture 6: Bacterial Motility + Introduction to pili/fimbriae Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are the different types of flagella?

A
  • Monotrichous
  • Amphitrichous
  • Lophotrichous
  • Peritrichous
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe Monotrichous flagella

A

Just one flagella at the end of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe Amphitrichous flagella

A

Flagella at either end of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe Lophotrichous flagella

A

multiple flagella at either end of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give an example of a bacteria that has Monotrichous flagella

A

Vibrio cholerae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Give an example of a bacteria that has Amphitrichous flagella

A

Campylobacter jejuni

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give an example of a bacteria that has Lophotrichous flagella

A

(Helicobacter pylori)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe Peritrichous
flagella

A

Grow flagella all over the cell i.e e coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give an example of a bacteria that has Peritrichous flagella

A

e coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What do motility patterns alternate between?

A

Run and tumble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe bacterial movement (run and tumble)

A
  • Run: motor rotates anti clockwise. The flagellar filaments form bundle and propel cells
  • Tumble: quick reversal of motor to clockwise rotation. This produces a twisting force that transforms the flagella into a righthanded helix. The bundke falls apart rapidly
  • Run: motor rotates anti-clockwise again. The flagellar filaments form a bundle and propel in a new direction.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 4 tactic responses of bacteria

A

Aerotaxis

Chemotaxis

Magnetotaxis

Phototaxis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe aerotaxis

A

movement usually towards oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe Chemotaxis

A

movement usually towards nutrients but also away from toxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Dewscribe Magnetotaxis

A

movement along lines of magnetism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe Phototaxis

A

movement towards light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Explain how chemotaxis in bacteria works

A
  • Transmembrane proteins called Methyl-accepting chemotaxis proteins (MCP) stick out of cells and detect and measure changes in environment
  • These interact with cytoplasmic proteins called che proteins which interact with rings of motor regulating direction in which it turns (dictate of the cell runs or tumbles)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is another name for MCP transmembrane proteins?

A

transducer proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How many different MCPs does e coli have?

A

5, which each detect different compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens when MCP interacts with sensor kinase CheA?

A

The sensor kinase CheA autophosphorolates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens when a bacteria is in the presence of an attractant?

A

The concentration of phosphorylated sensor kinase CheA decreases, anti-clockwise motion, longer runs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens when a v=bacteria is in the presence of a repellent?

A

The concentration of phosphorylated sensor kinase CheA increases, clockwise motion, more tumbling

23
Q

What does CheA-P phosphorolate?

A

CheY

24
Q

What does CheY-P bind to ?

A

The flagellar motor

25
Q

What happens when CheY-P binds to the flagellar motor?

A

There’s a change from anti-clockwise rotation to clockwise rotation, and the bacteria tumbles

26
Q

What dephosphorylates CheY-P?

A

A phosphatase, CheZ. This allows the anti-clockwise motion to resume

27
Q

How does a bacterial cell integrate the signals of attractants and repellants ?

A

By using CheR to methylate the MCP. The more methyl groups the MCP has, the less sensitive it is to the attractant and the repellent.

CheB increases methylesterase activity and the demethylation of the MCP

28
Q

Low conc. attractant

A

high CheA-℗, high CheB-℗

Demethylation of MCP, increasing sensitivity to attractant (longer runs)

29
Q

High conc. attractant

A

low CheA-℗, low CheB-℗

High methylation level of MCP, decreasing sensitivity to attractant, increasing autophosphorylation of CheA (more likely to tumble)

30
Q

is it true that each MCP receptor binds different ligands and different species have different optimum niches ?

A

Yes

31
Q

What is it called when a bacteria moves without the flagella?

A

Gliding

32
Q

Which bacteria is gliding common in ?

A

cyanobacteria

33
Q

How quickly does F. johnsoniae glide?

A

at up to 10 µm/s

34
Q

Describe how F. johnsoniae glides

A

Latex spheres added to F. johnsoniae bind to and are rapidly propelled along cells

Suggests that adhesive molecules move laterally along the cell surface during gliding

35
Q

What are the genes associated with gliding?

A

gld genes

36
Q

What happens if you disrupt gld genes?

A
  • You get a loss of motility
  • increases resistance to bacteriophages that infect wild-type cells
  • loss of the ability to digest the insoluble polysaccharide chitin
37
Q

Describe twitching motility via type IV pilus

A
  • Based on type IV pili first extending from cell surface then being retracted, dragging cell along surface
  • Powered by ATP hydrolysis
  • Retraction proteins control direction of movement
38
Q

Which bacteria can gas vesicles be found in?

A

In planktonic bacteria (e.g. cyanobacteria), and some archaea

39
Q

What are gas vesicles?

A

Protein vesicles that contain gas, which confers buoyancy to the cell

40
Q

Describe how gas vesicles work

A

Allow cells to float up to oxygenated water or towards the light

Can be involved in vertical migration in aquatic systems such as lakes

41
Q

What are fimbriae/pili?

A

Surface appendages, multi-subunit proteins

42
Q

What do fimbriae/pili do?

A

Allows for adhesion to other bacteria, host cells or environmental surfaces

43
Q

What are specialies pili associated with?

A

genetic exchange between bacteria

44
Q

How do some researchers distinguish between fimbriae and pili?

A

by linking pili to conjugation and gene exchange, but this is not always true

45
Q

What tests have defined at least 7 groups of pili?

A

Traditional agglutination tests

46
Q

What do agglutination tests use?

A

use yeasts, red blood cells, or tissue culture cells with or without mannose inhibition

47
Q

What are the most important pili?

A

type I and type IV

48
Q

Are fimbiae and pili major determinants of bacterial virulence?

A

Yes, they allow pathogens to attach to (colonise) tissues

49
Q

Is it true that fimbiae and pili sometimes aid resistance to immune cell phagocytosis?

A

Yes

50
Q

Because fimbriae are antigenic, what are there antigens called?

A

Colonisation Factor Antigens (CFA)

51
Q

What antibodies detect the fimbriae/pilli and block bacterial colonisation?

A

Secretory antibodies (IgA)

52
Q

What antibodies detect the fimbriae/pilli and catalyse phagocytosis?

A

Circulating antibodies (IgG or IgM)

53
Q

Role of fimbirae/pili in adhesion

A
  • Loose association of microbe with mucus
  • Pili and fimbriae allow microbe cell to stick to the surface of the epithelial cell. Tip protein binds to glycolopid receptors on epithelial cell.
  • Pili pulls microbe cloe to the host cell
  • Microbe becomes invasive (into or through submucosal epithelial cells
    )

-

54
Q
A

Infection Biology and Microbiology (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions